1. Field of the Invention
The present invention relates to cushions adapted for use as pads in seats of vehicles, such as automobiles, and in furniture, e.g., couches, chairs and the like.
2. Description of the Prior Art
Conventionally, various materials are used for cushions in vehicular seats and household furniture. The cushion materials include, for example, palmrock, formed of palm fibers, and synthetic foams such as polyurethane foam. A novel cushion has recently been developed. In this cushion, curled or crimped fibers of synthetic cotton are bound together by means of a bonding agent.
In general, cushions are required to have various properties, depending on their applications. Cushions for use as pads in vehicular seats, for example, are expected to have the following characteristics.
(1) Comfortableness. To be able to absorb vibration efficiently, have their bearing surface free from deviation in pressure distribution, and be moderately flexible.
(2) High durability. To be subject to less permanent set in fatigue after repeated use.
(3) Good air-permeability. To be agreeable to the skin after prolonged sitting, without becoming stuffy or heavy with moisture and heat.
A conventional cushion formed of palmrock cannot enjoy characteristics (1) and (2). On the other hand, synthetic foam cannot fulfill requirements (2) and (3).
In order to produce cushions which fulfill all of requirements (1) to (3), the inventors hereof have been attempting to develop improved cushions in which fibers of synthetic cotton are bound together by means of a bonding agent. Since those cushions in car seats are used under severe conditions, however, they cannot easily fulfill all the aforesaid requirements. If one such cushion is formed of fibers with the denier value over 50, for example, then it has too stiff a surface to be agreeable to the touch, and is poor in durability. Also, the fibers are so rigid that the cushion cannot be easily formed into a desired shape. If the cushion is formed of relatively fine fibers with the denier value of less than 20, on the other hand, it is agreeable to the touch, enjoys high durability, and can be easily formed into a desired shape, due to the low rigidity of the fibers. In this case, however, the cushion is so poor in air-permeability that it will become stuffy or heavy with moisture and heat after prolonged sitting.